Insulator.



L. M. RANDOLPH.

INSULATOR. APPLICATION FILED 0CT.17, 1910.

.wlQ Patented Aug. 13,1912.

LEGNARD M. RANDCXIJTH, OF NEWARK, NEW JERSEY.

INSULATOR.

Specicatoniof Letters Patent. Patented A110'. 12.3, 1912.

Application filed October 17, 1910. Serial No. 587,372. I

To all 'whom it mfg/concern:

Be it known that I, LEONARD M. RAN- noLrH, a citizen of the United States, and a resident of the city of Newark, in the county 'of Essex and State of New Jersey, have in- -vented certain new and useful Improvements in Insulators, of which the following is a specification, reference being had to the ac-v companying drawing, forminga part hereof. Porcelain, on account of its comparative cheapness, convenience in molding, and good insulating qualities, is desirable for use in the manufacture of insulators vof various kinds; but owing to the ditliculty of molding metal parts therewith', such as is required in certain types of insulators, other' and less desirable substances have been employed. It is true that attempts have been made to mold metal parts: .in porcelain insulators, though such attempts have generally failed on account of the dilerence in the expansive properties of the metal and porcelain. 'Moreover metal parts have been cemented in-porcelain but in .use they generally Work loose .from vibration and other causes and become detached from or result in the fracture of the porcelain.

The object of the present invention is to provide a construction whereby it will be v possible to malte use of porcelain in insulators requiring metallic parts without encountering the diliiculties heretofore men-` tioned.

In accordance with the present improvements, the body portion of the insulator with which the metallic parts are associated is formed of an insulating composition havi ing substantially the same coefficient of expension as that of the metallic parts, and.v 40 compensating means are provided for unit-l ing the body portion with the porcelain part.

The single figure of the drawing represents a central vertical section taken through an insulator of the suspension type, though it will be understood that the inventionmay be embodiedin insulators of various types and that the lpresent type is chosen as illustrative merely. 1.* Y The body portion of the insulator, indicated at (a)`,'has embedded therein a suspending bolt (1)) and a metallic cup piece (c) the head (d) of the bolt extending up into th'cup (c) beyond the flange (c) thereof, as in similar constructions. The insulat- 5 lng composition constituting the body-'pon tion (a) may-be of any suitable substance or combination of materials which is moldable with the metallic partsand which hassubstantially the same coeiiicient of expansion as these parts. Most of the gummy or resinous insulating compositionswould answer this purpose, applicants own composition derived from the residue of varnish kettles and known as varnish residue-being preferred. The other portion of the insulator, namely the portion surrounding the body portion, is generally made up of what is referred to as a petticoat or petticoats. In the present case this portion of the insulator consists of a flaring piece (f) open at the center .so as to slip on the body portion' of the insulator from the top and rest down upon a shoulder (h) formed upon the body port-ion. While the present improvements were designed so that porcelain, which has la different coeiicient of expansion from that of the body portion and the metallic parts, mav bc used to make the petticoat, it will be obvious that other suitable materials may be .used therefor. Porcelain, however, is preferable.

To unite the porcelain pet-ticoat to the body portion, means must be dprovided which shall compensate for the iii'erence in the-expansion properties of the petticoat. and thel body portion and at the same time prevent the petticoat from vibrating or rattling upon the body portion. Such means may preferably comprise a metallic Iring (g) -threaded upon the cup (c) orn per part of the body portion which bears own upo thepetticoat (f) and a layer of plastic or` soft material (l) interposed between the ring and.body\portion on the one hand and the petticoat on the other. This soft plasz tic material preferably consists of a mixture of oil, paraffin wax, and red oXid of iron although many other plastic waterproof mixtures may serve as well 'uch for example, as partially vulcanized rubber. Moreover, the petticoat is preferably formed `with a flange (i) around the central open- -ing and the ring (g) with an outwardlyand downwardly extending iange (a"`)\` ject over the flange (i) in orderl toie ectively retain the tticoat in position and to a'ford a watertig t jnt between the same andthe body portion..

It will be obvious-.that more `than one7 petticvoat maybe employed, that various other forms of porcelain parts may be added .tothebody portion which are not, properly speaking, Apetticoat'sj and that t constructionA set Iforth here may be otherwise departed from'and added to without departing from the spirit' of the invention. -AI claim as my inventionz-` l. In an insulator, the combination with a body portion, and `metallic parts molded therein, said body portion having substan. ti'ally the same coetlicient of expansion as the metallic parts, of a pctt-icoat having a different coeicient of expansion, and compensating means to unite the pettieoat to the body portion of the insulator.

2. ln an insulator, the combination \vith a body portiomrand metallic parts molded therein, said bodypor-t-ion having *substantially the same coefficientof expansion as the metallic parts, of a petticoat having a diierent coeicicnt of expansion, and means including a plasticfwaterproof medium for uniting the pet-ticoat to the body portion of the insulator. f

3. ln an insulator, the combination with a body portion, and metallic parts molded therein, said body portion having substantially the same coetlicient of expansion as the metallic parts, of a petticoat hav-ing a different eoellicient of expansion, the body portion of the insulator being formed so as` to sustain the petticoat, and a ring bearing against. the top of the petticoat to hold it against the body port-ion.

4. In an insulator, the combination with a body port-ion, and metallic part-s molded therein, said body portion having substantially the' same coeliicient of.. expansion as the metallic parts of a petti'c'oat lia-ving a different coeiiicient of expansion, the body portion of the insulator being formed so 'as to sustain the petticoat, a metallic ring threaded to the body portion and bearing down uponthe top of the pettcoat, a circular'tlange on'the ring projecting over the top of the petticoat, and a layer of plastic material. interposed between thering and body portion on the one hand and the petticoat on the other. A

5.In an insulator, the combination with a body portion of insulating composition, and metallic parts molded therein, said insulating composition having substantially the saine coeicient of expansion as the metallic partsfof a porcelain Petticoat, and compensating means to unite the petticoat to the body portion of the insulator.

` This specification signed and witnessed this 10th day of October, A. D. 1910.

'LEONARD M. RANDOLPH.

Signed in the presence olf- JoHN W. THOMPSON, LUoIus E. VARNEY.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents.

. Washington, D. C.y 

